A word from Chip, the 'Headless Guy' costume creator:

I made this costume from different products that I could buy seperately but not at the same time nor from the same companies, I have many variations of it, including Gaga-Ween (headless Lady Gaga), Headless Ozzy Osbourne, and Headlessly Married.
Hope this makes it into best adult costume.

Looks pretty damn realistic. One of the best headless costumes I have seen yet. Great job with the neck detail. Overall I think this one might just be the best yet at least the best I have seen for a homemade headless costume. Can't wait to see what you come up with next I'm sure it will be bad Ass!!!!